The ancient traditions and sacred rituals of Yamaoka village determine the fate of its people while Hikari Tsukimura carries the inherited power of the Kanshisha who judges souls. Her heart-scanning talent enables her to enforce justice with absolute determination. When Hakari succumbs to forbidden magic her ingrained sense of duty becomes entangled with family loyalty in an unprecedented manner. Hakari who used to take pride in his warrior status and his place as his father’s successor now feels deep bitterness because he never received the power that belonged to him. Desperate to carve his own path, he turns to a long-forgotten relic: The Immortal Mask is a legendary artifact said to bestow divine power to its wearer at an exorbitant price. The creeping corruption of the forbidden magic consumes Hakari's body and mind and transforms him into a dark figure that replaces the boy Hikari once cherished with something monstrous. Hikari learns the terrifying origin story of the mask when he discovers an ancient evil awakening under what was believed to be the deserted ruins of Kurohana Village. She sets off on a mission to prevent her brother's transformation into an irredeemable force as her warning beads glow and past Arbiters whisper guidance to her. Hikari faces both Hakari’s expanding strength and her own internal uncertainty as she tries to stop him. Will she be able to pull him back from the brink or is he already beyond salvation? As war looms, family fractures, and darkness threatens to consume them all, Hikari must make an impossible choice: Save her brother—or judge him.